Microprocessor modules have become popular in recent years as a means for providing reliable and efficient computer system upgrades. In a microprocessor module, a processor is mounted to a circuit panel containing electrical interconnection paths, for example a printed circuit board, along with support electronics, for example random access memory (RAM) in the form of processor cache. Module electronics communicate with electronics mounted to a computer motherboard via an interface in the form of a high-speed connector. Ideally, as system clock rates increase, and processor functions evolve, the outdated microprocessor module assembly can be removed from the motherboard at its connector and replaced by an upgraded module capable of operating at the higher rate, and/or with improved functionality.
A straightforward processor module replacement is not necessarily achieved by contemporary systems. As processors become faster, the underlying silicon gate technology becomes smaller, and therefore requires a different, for example, an increasingly lower, supply voltage level. The lower voltage level required by the upgrade processor module is thus exceeded by the voltage supplied by the original voltage regulators commonly mounted directly to the motherboard designed specifically for use with the former processor module. For this reason, the upgrade processor module may be incompatible with the existing motherboard. Therefore, processor module upgrade currently involves not only replacement of the module at the module connector, but also removal and reinsertion of, or reprogramming of, voltage regulators mounted to the motherboard.
This is complicated by the fact that often times, within the module itself, the processor utilizes a different supply voltage than that of the support electronics, for example cache RAM, the multiple supply voltages being generated by the multiple voltage regulators mounted to the motherboard. Module replacement in this case therefore requires the additional replacement of the multiple voltage regulators on the motherboard.
Additionally, as processor module supply voltages decrease, and clock rates increase, processor module power consumption generally remains constant, and, as a result, the current draw for the module increases. Since modem processor modules have current draws on the order of 50-70 Amperes, sophisticated connectors are required to mitigate what otherwise would be significant voltage drops at the module connector due to inherent resistance and inductance at the connector terminals. Such specialized connectors are expensive and bulky, and are therefore undesirable in modular computer systems.